Automatic snap-acting fluid pressure inflator



b May 12, 1953 R. L. STURMER 2,638,113

AUTOMATIC SNAP-ACTING FLUID PRESSURE INFLATOR Filed July 27, 1949 2 Sheets-Sheet l 33 i F76. 6'. 44 q J3 42 g I r 4 47 I: I, 2 2 O 56 \La/ INVENTOR f; J E 7 005557 zsflar J'TURMER 3,2 i I 13 Y I 451 m2 8 MQWWM 39 40 9 ATTORNEY M y 12, 1953 R. L. STURMER 2,638,113

AUTOMATIC SNAP-ACTING FLUID PRESSURE INFLATOR Filed July 27, 1949 2 Sheets-Sheet 2 LL 7 INVENTOR 7- /1 215 J F a} 435 a V1 wafer 46/?07 0mm BY l/A I 4 Z36 %J 1.,

ATTORNEY Patented May 12, 1953 AUTOMATIC SNAP-ACTING FLUID PRESSURE INFLATOR,

Robert Leroy Stunner, San Leandro, Califi, as-

signor to Nelson Specialty Corporation, San Leandro, Calif., a corporation of California Application July 27, 1949, Serial No. 107,090

9 Claims.

' My invention relates to improvements in automatic inflating devices for use with compressible fluids, and more particularly to improvements in quick acting automatic inflating devices of the, single diaphragm type.

' An important object of the invention is to provide an accurate, automatic, and quick acting inflating device of simplified design and single diaphragm construction. I

Another object of the invention is to provide an accurate and automatic device for rapidly inflating vehicle tires which is adapted to be incorporated into a flexible pneumatic supply line and readily moved about therewith.

' A further object of the invention is to provide a .quick acting automatic inflating device for vehicle tires and the like which possesses improved accuracy and which is relatively quiet in operation.

, Another object of the invention is to provide an accurate and quick acting automatic inflating device for use with compressible fluids which provides long filling strokes, and which can be adjusted easily to the desired pressure by the operator immediately prior to or during use.

1 A still further object of the invention is to provide an accurate and quick acting automatic tire inflating device which is readily portable and which can be readily adjusted to a predetermined pressure by the operator immediately prior to or during use.

Another object of the. invention is to provide alight weight and readily portable automatic tire-inflating device which possesses improved accuracy and can be readily disassembled. for

cleaning and repair.

I "A further object of the invention is to provid an accurate and quick acting automatic device for inflating pneumatic tires to a predetermined pressure which maintains its calibration with continued use independently of normal variations in supply tank pressure.

It is another object of the instant invention to provide an accurate and quick acting autoinatic tire inflator of simple design,'readily fabricated in quantity at a low unit cost.

Further objects are to provide a construction of maximum simplicity, economy and ease of assembly and disassembly, also such further objects, advantages and capabilities as will fully appear and as are inherently possessed by the device and the invention describedherein.

Invention furtherresidesin the combination, construction and arrangement of parts shown in the accompanyingdrawings and. while there is 2 shown therein a preferred embodiment thereof, it is to be understood that the same is merely illustrative of the invention and the invention is capable of modification and change and comprehends other details of construction without departing from the spirit thereof or the scope of the appended claims.

Referring to the drawings:

Figure 1 is a perspective view showing the automatic inflating device, with the dial cap and the key raised from the assembly to show their relative positions. I

Figure 2 is a longitudinal vertical section showing the device of Figure 1 connected toa r source of fluid under pressure with the valve closed and the dial set to a low value.

Figure 3 is similar to Figure 2, but shows the dial set to a high value and the control valve in the open condition.

Figure 4 is a top plan view of the device of Figure 1, showing the indicator dial.

Figure 5 is a sectional view of the central housing taken on the-plane VV in Figure 2, and looking in the direction of the arrows.

Figure 6 is aplan view of the bottom cover assembly which corresponds with the line VI-VI in Figure 3, and looking in the direction of the arrows.

Referring now more particularly to the drawings in which like reference numerals indicate like parts in the several views, an automatic device for inflating vehicle tires and the like is shown generally at I0. It involves three principal assemblies, one in the central casing or housing II, the second in the topcover member I2, and the third in the bottom cover member I3. These three members are preferably die-cast from a suitable light metal alloy. The top cover I2, together with the retaining ring I4, are secured to the housing II by means of recessed screws Ma or in any other suitable manner for quick access or assembly. The bottom cover member I3 is secured to the under surface of the housing II by screws I3d which pass upwardly through holes I3a and engage threads in the internal bosses Nb of the housing.

The central portion of the top cover l2is drilled and tapped to receive and engage the threads of the lower portion I5a of a short vertical shaft I5. The upper portion I 5b of this same shaft I5 has a transverse slot I adapted to receive the floating key I6. Bushing I! which is supported by the upper portion of the cover I2 and which surrounds the upper portion I5b of the shaft I5, is likewise provided with a trans-v verse slot [it so that when the key It is in place the bushing Ill and the shaft l rotate a a unit. Bushing l! is rotatably supported within the annular recess Na in the cover member 12 and retained therein by the ring M for free turning movement in a horizontal plane about the axis of shaft Cap l8 fits as a bonnet over the ring l4 and over the exposed portions of the bushing l1 and shaft l5 when keyed together with key [6, and cap i8 is retained in position, adjustably, by set screw which bears against the vertical cylindrical surface lia of the bushing l1. Thus when the cap It is rotated, bushing it will rotate and the shaft 15 will also rotate and move either up or down on its thread [5a depending upon the direction of rotation; The flanged surface of the cap it carries a graduated scale 21 which coacts with the arrow or pointer 22 on the cover member l2. The cap it is not intended, under usual conditions, for unlimited rotation. Accordingly, stop it is provided on the surface of the retaining ring M, which stop is adapted to guide in circular groove Eda for-med in the under surfac of cap i8, which groove is not completed between the lowest, and highest dial readings thereby providing a barrier to 360 degree rotation.

The central housing Hf is provided with a vertical'bore 25 substantially in axial alignment with shaft t5. A stiff compression spring iii) of relatively large diameter is retained within the bore 25. The upper end of spring 26 bears against and exerts an upward resilient pressure on the plug or; cap 21.. The ball end 28- at the inner terminus of the shaft it bear against a centrally disposed detent 27a in the upper surface or plug 2'1. In this manner the. resilient pressure of spring 26 is transmitted to shaft 15. The lower end of spring 26 exerts a downward resilient pressure against the upper surface of the cylindrical diadiaphragm 36- is retained in position on the shoulder Baby the tubular bushing 32- which extends upwardlyto abut against the lower face of the casing or housing it. The bottom cover member [3, the diaphragm 36, and the tubular bushing 32 are maintained in position by the screws ISd; which pass therethrough and engage threads in the bosses lib of the central housing. The diaphragm head 33 rests upon the uppersurface of the diaphragm 36, and is adapted for vertical movement within the tubular bushing 32. However, since the diameter of the head is substantially greater than that of the vertical bore 2-5, itsupward movement in opposition to the action of spring 26 is limited by the lower face, of central housing ll. 'llhe diaphragm head 30 is slotted longitudinally of the device from its top for about three-quarters of its height, thusretail-ling a flat continuous lower surface for contact with the. upper surface of the diaphragm 35. This longitudinal. slot is. adapted to receive longitudinal cam 42 which is held in position within the. slot for pivotal movement in the verticalplane by a. horizontal pin M which. passes through the head 3H. and the. cam Q2. The pin ll extends beyond the head 33 on both sides thereof, and

these ends are iournalled in hardened loose cy lindrical sleeves 40. These sleeves 40 ride in and engage a pair of relatively narrow vertical slots 29 cut transversely at diametrically opposed positions in the wall of the annular bushing 32 and the sleeve 40 preferably bear against hardened inserts 33 on the. bearing face of each slot 29. A pair of relatively wide vertical slots 33 are also formed in the bushing 32 in a plane substantially at right angles to the slots 29 and the axis of pin 41, the slots. 29 and 33 being disposed in quadrature arrangement. One end of the cam 42 is provided with a bifurcated yoke or fork 44, and is retained in limited free movement by transverse pin 65 extending across one of the slots 33, the diameter of pin 45 having a predetermined relationship to the distance between the upper and lower tynes of fork M. The opposite end of cam 42 is provided with an upper beveled cam surface 43a and an oppositely and more sharply beveled lower cam surface 431)., the surface 43a and .4372 being adapted to. coact. with the shape. spring roller 46. which rotates about. a pin 3] carried by the free end of a, relatively stiff leaf spring 57. The opposite end ofspring; 41. is: sup: ported upon the. upper surface of the housing II as shown in. Figure 2, and is retained in position when the uppercover plate 12 is. attached. As. indicated by the configuration of the cam sur-.. faces 13a and L t-b, more force is required to: raise the end d3 of cam 12 from the lower position shown in Figure 3 to. the position shown. in Fig-.-. ure 2 than is required to depress the cam. Spring M, being in constant. Contact. with either one or the otherof' the cam faces 413a and 43b, continuously exerts a. resilient. pressure which causes; the rollers 29- tobear against the hardened plate. 33.

A bleeder passage 5.3 communicates from the outflow port 25 of the central housing llv with passageway 541 in the. bottom covermember l3 through a spring loaded check; valve 55. having: a bypass or leakage passage 5.5a of predetermined size formed therein such a manner as to. ime. pede or retard the equalization of the pressure in the chamber 38 with the pressure in the out. flow port 2%, whenever the; outflow pressure in the delivery line M is increased. However, the, c ck valve 55- qui'ckly e uali zes; the. pressure. in chamber 38 with that. of outflow port 21 whens ever the pressure in chamber 328: is. higher than, the pressure in the delivery line 34. and. the dif'sv ferential pressure is sufiicient to. overcome the resistance ofthe valve. spring 56. (N. B. Pass sage 54. leads, directly to. chamber 38,).

When the snap-acting car-n i2 is in the raised position illustrated in Figure 2: wherein the roller 4:6. is in contact with the lower camsurface 43b and retained there. by the resilient action of spring 11, the upper tyne of: the tort: 4 2i bears downwardly in contact with the pin 45 and out, ofengagement. with thelower end 51 of the valvestem 58. A decrease in the pressure in chamber 3.8; of a sufiicient value willpermit the spring 26; to. more. the. head 3.3 downwardly and with it. pin l I; so. that. the; cam 43 is caused. to. move. past. dead center and to. its, lower position, which illustrated in Figure 3:, wherein the roller 46 is brought into. contact. with carnsurface 43a. In. this position the. lower tyne of the fork 44- moves, into contact with the pin 45, causing the fork member Min to bear against. the lower end 51 to unseat. the. valve 53. from. substantial fluid-tight sealing engagement. with the member 61, and in opposition to. the action of the valve spring 60. In this; manner, the Malve 39' is; opened to a. pro

determined value determined by the clearance between the pin 45 and the fork members 43a and 43!).

Valve seating member 61 has a hollow cy r cal body 88 having formed integrally therewith an inner sealing ring 66 and the parallel and spaced apart outer peripheral rings 69 and 10. The upper surface of the outer ring forms a shoulder for supporting an O-ring seal H .at the top of the member 61, and extendingtransverse- 1y through the body 68 thereof between the outer rings 69 and 10 is one or more air inlet holes 12. When the member 6! is inserted and seated within a vertical bore 13 drilled in'the upper portion of the central housing i I, the annular space bounded by the body 68, the bore 13, and the rings 89 and 78 forms an outer fluid chamber 14. Thus, pressurized fluid from the supply line 35 passes from the inflow port 23 through the passageway 83 in the central housing II into the outer chamber 14, which communicates with the interior chamber 64 within the seating member 81 through the holes 12. An O-ring seal 15 is placed around the lower portion of the valve stem 58 before the lowermost end 51 thereof is inserted through a hole 18 counter-bored in the lower portion of the housing I l with its axis substantially in alignment with the axis of vertical bore 13. After th valve stem 58 has been lowered sufficiently to move the valve 59 into seating engagement with the seat 66, the valve spring 60 is installed on the upper portion 58a of the valve stem so that the lower end of the spring presses downwardly on the valve 59 and the opposite end of spring 60 exerts upward resilient pressure on an O-ring seal H contained within the cylindrical recess 18 in th lower face of the top cover. This cover l2 has a vertical hole 82 counter-bored therein in such a manner as to slidably receive the upper end 58a of the valve stem as the valve 59 moves to the open position, and this hole 62 communicates with the atmosphere through clearance between the retainer ring l4 and the housing II. The respective upper and lower portions 58a and 51 of the valve stemare of substantially the same diameter, and the upper stem 58a is retained in sealing engagement at all times with an O-ring seal 71 which is substantially the same size as the seal 15 which forms a sealingengagement with the per seal 1'! whenever the valve is open, and isalso pressure balanced between the upper and lower ends of the inner chamber 64 whenever the valve is in the closed position. Because of this pressure balance in both the open and closed positions of the valve 59 and valve stem' 58, the operation thereof is substantially independent of compressor or supply line pressure fluctuations which may normally be expected to occur during tire inflating operations or recharging of the air storage tank. Whenever the valve stem 59 is .moved to its raised position bythe action of cam 42 and yoke 44, a predetermined volume of pressurized fluid is permitted to flow from the inflow port 23 through the passage 63, into valve chamber 64, through the valve 59, and into the outflow connection 24 and the delivery line 34.

Operation In operation, the in-flow port 23 is connected by a flexible hose to a source of compressed 6 more per square inch greater man the pressure to which the tire is to be inflated, and the outflow port 24 is connected to a relatively short delivery supply line 34, the free end of which contains a delivery chuck or valve 52 which is adapted to be removably connected to the valve stem of a pneumatic tire or other inflatable receiver. The graduated scale 2|, which preferably is calibrated in pounds per square inch, is turned about its vertical axis so as to indicate the desired tire pressure opposite the fixed pointer 22, thereby adjusting the downward pressure exerted by the stiff spring 26 on the head 30 and its supporting diaphragm 36 to a predetermined value, Under conditions wherein the delivery line 34 is placed in communication with a tire or other pressure vessel, the pressure of the line 34 and the cham ber 38 will be equalized with that of the vessel, through the passage 53 and the check valve bypass 55a; Whenever pressure in the chamber 38 is lower than the pressure indicated by the dial 2 I, the resilient action of the stiff spring 26 pressing downwardly on the diaphragm head 30 moves the head and its supporting diaphragm 318 downwardly together with the central portion of the cam 42 which is pivotally supported by the pin 4 I. Since the fork 44 is restrained in its vertical movement in a predetermined manner by the horizontal pin 45 carried by the fixed bushing 52, the free end of the cam 42 is caused by the vertical movement of the central cam portion to move past dead center so that the cam 42 comes to rest in its lowermost position wherein the cam surface 48a is in engagement with the snap spring roller 46, as shown in Figure 3. This snap or toggle action of the cam 42 about the pin 4| as an axis brings the fork member 44a into contact with the lower end 5? of the valve stem 58 so as to raise the stem and unseat and open the valve 59 a predetermined distance determined by the vertical movement of the yoke 44. The opening of the valve 58 permits pressurized air to flow from the valve chamber 64 downwardly past the valve 58 and into the tire through the passage 66 and the delivery hose 34. The increased pressure which is thereby developed in the outflow port 24 causes back pressure to flow through the passage 53, slowly past the check valve 55 at a rate primarily determined by the size of the leakage passage 55a, and into the chamber 38 causing the diaphragm 38 to move the head 38 and pivotally connected cam 42, upwardly past the dead center position, with the result that the cam 42 comes to rest in its initial position illustrated in Figure 2 wherein the lower cam surface 43b is in engagement with the snap-ring roller 46, at which time the upper tyne of the fork 44 again moves into During this quick contact with the fixed pin 45. acting toggle movement of the cam 42, the downward motion of the fork 44 permits the valve stem 58 to be lowered by the valve spring 68 to quickly close the valve 59 and thereby interrupt communication between the delivery hose 34 and the high pressure supply line 35. Upon closure of the valve 59, the pressure in the delivery line is rapidly dissipated into the tire, and the ball check valve 55 permits the pressure in the chamber 38 to quickly balance with the pressure in the tire.

Thus, it will be seen that successive cycles or' pulsations will be initiated by the diaphragm actuated cam42 as long as the tire pressure is bepressure in the tire and in the diaphragm cham-v her 38: is substantially equal to the; predetermined downward resilient: pressure ofthe spring 25' whi h. corresponds with a. particular setting of. the: indicator dial. 21-. As soon as the desired. tire pressure has been attained, and the pressure. in the tire and in the chamber 38. is substantially equal to thepressura cheated by the dial; 2'! the cam; 42 will be retained its raised. position above. the; roller it: as. illustratedin Figure 2;. and no; furtherpulsations of. the device will occur; thereby indicating to the operator thatautomatic inflation of; the tire has been completed.

I-. claim:

11. In automatic: apparatusfor dispensing pres Surized fluids; the combination which comprises a chamber: adapted to continuously receive fluid: from a higb. -pressure source, a valve: in said" chamber having means normally biasing. saidi valvein the-closed. position, and out-flow passage v way adapted! to; be placed in communication: with the-said chamber whenever the said valve is. in the; open position, a diaphragm forming, an ex+- pansible chamber; responsive. to variations in: pressure in the.said..out-fiow passageway, floatingsnapeacting; means-including. a snapspring and a cam supportedon said diaphragm, primarily controlled by the expansionand contraction: of the said expansible; chamber and adapted to open and to; permit. closing of the. said valve, and. ad

lusting means operable to. exert a set. resilient pressure on the-lsaidfloating snap-acting means oppositionlto; the action of the said. expansible sham-ten.

2;. Ira automatic. apparatus. for dispensing pres Suriaedfluids; the combination which". comprises a; chamber adapted to continuously receive. fluid" iirom ahigh-pressure source; apressureba'lancedvalve; in said; chamber having means normally" biasing; said" valve. in. the: closed. position, an out-= flow passageway: adapted to: be placed in: com-- munication with the said.chamber-Whenever'the saidvalve is in the openposition, a diaphragmforming an. eX-pansihle chamber responsive to puessurevariationg: inthecaid. out-flow passage-- Way.- and connected thereto through a flow-re strioting; opening, snap-actin means including a snap spring; and a cam supported: on: said die-- phragm,primarily; controlled by the expansion and contraction"; of; the: saidv expansiblei' chamber and adapted to actuate theisaidva'lve, and ad- J'ustable; calibratedoperable to exert a downward set: pressure on the; said" diaphragm= supported; snap-acting; means. in opposition tothe action; of. the said expansible: chamber.

3. Inautomatic;apparatusrfor dispensihg'presceive fluid-under pressure from the said chamber when. the said-valve: is in the open position, an expansibiechamber having: a pressure-sensitive diaphragm, means communicating said chamber withlsaid deliveryconduitincluding a valve-allowing-"relativelyfree and rapid passage of flil-id 3 from: the;. chamber; to the delivery conduit and" relatively slow passage; of': fluid "in-1 the opposite direction,..snap.-;acting means including a snap" sprinaand ,:a i cam supportedromsaid' diaphragm}.

controlled by the expansion and contractionofi the said diaphragm and adapted to actuate the said valve, and means adjustable externally of said housing and operable to exert a downward resilient pressure on the snap-acting cam in opposition to the pressure exerted on said dia phragm in the said exp'ansible pressure chamber.

4. In automatic apparatus for dispensing pressurized fluids, the combination which comprises a chamber adapted to receive fluid from a high-- pressure-source; a pneumatically balanced valve in saidchamber having means normally biasing said valvein the closed position, a delivery 0011- duit adapted to be connected with an inflatable. receiver and to be placed in communication with the said chamber, an expansible chamber having a pressure-sensitive diaphragm, means communi-' eating said chamber with said delivery conduit including: a valve allowing relatively free and rapid passage of fluid from the chamber to the, delivery conduit and relatively slow passage of. fluid in the opposite-direction, snap-acting meansincluding a snap spring and a cam pivotally supported on a diaphragm head, primarilycontrolled by the expansion and contraction of the said dietphragmin such a manner'as to actuate the said. valve, meansv operatively connecting said sham" acting means and valve, and adjustable means. operable to exert a predetermineddownward-resilient pressure. on the said diaphragm-head tend ing to oppose the upward movement ofthe; saiddiaphragm.

5. Automatic inflating apparatus comprising an air inlet, an air outlet means connecting the same'for passage of air from the inlet to-theout let, a normally closed valve disposed in said connectingrneans forvnormally closing communica'- t-ion between the inlet and outlet, pressure re sponsive means communicating withsaidoutlet, valve operating means mounted on, supported. and operated by said pressure responsive means to open saidvalve When-the pressure in thegoutlet. is less than a setvalue, calibrated means, for: adjusting said pressure responsive means to change the said. setvalue and snap-actingmeans; including, a snap spring and a cam supportedon said diaphragm, for quickly operating said valve; operating. means.

6. Automatic inflating apparatus comprising. air inlet, an airoutlet, means connecting the same for passage of airfrom the inlet to-the-Out let, a. normally closed valve disposed insaid conheating means for. normally. closing.v communica'e tion between the inlet and outletrpressure re.-- sponsive means communicating. with said outlet, valve operating-means in the form of a lever-car ried. by and pivoted on said pressureresponsive' means for movement therewith, oneendofsaid, lever being in operative relation tosaid valvefoi" opening the same by. pivotal movement in one direction and ts allow closing; of the same by piv faces toquick-ly operate said lever 05' snap. action? both toopen and toperm-it closing of said valve! 7. Automatic inflating apparatus comprising; an-alr inlet, an air outlet, means-connecting ithe same for passage of=air from the inlet to the-out.

- let; anormallyrclosed vaive disposedin Samson:

necting means for normally. closing communication between the inlet and outlet, a pressure responsive diaphragm communicating with said outlet: and dlr ectly responsive to the pressures. thereof; valve operating -means=includirig a ply otally mounted lever carried by said pressure responsive diaphragm for movement therewith, one end of said lever being in operative relation to said valve for opening the same by pivotal movement in one direction and to allow closing of the same by pivotal movement in the other direction, the other end of said lever having divergent cam surfaces, and resilient means for bearing against said cam surfaces for quickly operating said lever by snap action as it passes from one of said surfaces to the other.

8. In automatic apparatus for dispensing pressurized fluids, the combination which comprises a casing having a central bore, a separated inner chamber in said casing having valve means therein operable to control the pulsating flow of pressurized fluids through said chamber, an inflow connection for the said chamber, an outflow connection for the said chamber, a diaphragm across said central bore forming a fluid pressure chamber communicating with said outflow connection, a snap spring in said casing, means supported on said diaphragm including snap acting cam means coacting with said snap spring, responsive in a predetermined manner to the pressure at the said outflow connection and operable to control the action of said cam means to move the said valve from a normally closed to a predetermined open position, and means adjustable externally of said housing for exerting a set downward resilient pressure on the said diaphragm and dia- 'phragm supported means.

9. In automatic apparatus for dispensing presintermittently communicate the said chamber with an outflow connection, a diaphragm form- 1 ing a fluid pressure chamber in said bore communicating with said outflow connection, a snap spring in said casing, a member supported by said diaphragm carrying snap acting cam. means ccacting with said snap spring, responsive in a predetermined manner to the pressure at the said outflow connection and operable to control the action of the said cam means to move the said valve from a normally closed to a predetermined open position, and means adjustable externally of the housing for exerting a set downward resilient pressure on the said diaphragm supported member and said diaphragm.

ROBERT LEROY STURMER.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,618,953 Penn .r Feb. 22, 1927 1,770,912 Clapp July 22, 1940 1,861,916 Hennebohle June 7, 1932 1,918,341 Knaak July 18, 1933 2,294,702 Van Der Werff Sept. 1, 1942 2,344,256 Lyons et a1 Mar. 14, 1944 

